Close all the Divi accordions on page load. Works with Divi 2.5 and above

common.js

/**
 * Toggle the class on the accordion so that they're all closesd on page load
 */
jQuery( document ).ready( function( $ ) {
	$(function() {
		$(".et_pb_accordion .et_pb_toggle_open").addClass("et_pb_toggle_close").removeClass("et_pb_toggle_open");

		$(".et_pb_accordion .et_pb_toggle").click(function() {
			$this = $(this);
			setTimeout(function() {
				$this.parent().removeClass("et_pb_accordion_toggling");
			}, 700);
		});
  	});
} );

functions.php

/**
 * Enqueue our theme scripts & styles
 */
function child_scripts_styles() {
	// Enqueue our common scripts
	wp_register_script( 'commonjs', trailingslashit( get_stylesheet_directory_uri() ) . 'js/common.js', array( 'jquery', 'divi-custom-script' ), '1.0', true );
	wp_enqueue_script( 'commonjs' );
}
add_action( 'wp_enqueue_scripts', 'child_scripts_styles' );

instead of creating a separate JS file and then enqueuing it using functions.php file we can paste that code in DIVI Theme options or in a code module.
Using the code module is the best approach as it will load the JQuery code on the only required page.